<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.8.0.js">
    </script>
</head>
<script>
    $(document).ready = (function() {
        $('#username').blur(function() {
            $.post('./jquery.php', {
                user: 'zhangsan',
                pwd: 123
            }, function(data) {
                console.log(data);

            })
        })
    })
</script>

<body>

    <body>
        <form action="">
            用户名：<input type="text" name="username" id="username">
            <input type="button" name="" value="注册" id="btn">
        </form>
        <div class="gg" id="gg"></div>
    </body>
</body>

</html>